Abstract: As shown in FIGS. 1 and 2, in a pneumatic tire of the present invention, block-shaped land portions 18 are divided by main grooves 14 and lug grooves 16 on the tread 12 of a studless tire 10 and a plurality of transverse sipings 20 is formed on each of the block-shaped land portions 18. Each sipings 20 is formed from a first linear portion 20A, a second linear portion 20B, and a sloping line portion 20C. The first linear portion 20A essentially extends in a direction perpendicular to the surface 18A of the block-shaped land portion 18 and contacts the surface 18A, the second linear portion 20B essentially extends in a direction perpendicular to the surface 18A and is separated from the surface 18A, and the sloping line portion 20C inclines to connect the ends of the first linear portion 20A and the second linear portion 20B. In each of the sipings 20, the position D1 of the sloping line portion 20C is set to 10% to 60% of the siping depth D.

Abstract: Disclosed is a pneumatic tire effectively controlling uneven wear occurring in the vicinity of a main groove even if a groove width of the main groove is widened due to change in tread radius during inflation. In the pneumatic tire, with regard to a zigzag-shaped main groove having the groove width widened during inflation among a plurality of main grooves provided on a tread surface, an inclination angle of a groove wall near the center with respect to the tread surface is made relatively large in a bent portion near the shoulder, an inclination angle of a groove wall near the shoulder with respect to the tread surface is made relatively large in a bent portion near the center, and regions where the inclination angles of the opposed groove walls are different from each other are uncontinuously arranged in the tire circumferential direction.

Abstract: A pneumatic tire comprises a pair of bead portions, a pair of sidewall portion, a tread portion, a radial carcass of at least one ply, and a belt, wherein the tread portion is provided with two or more circumferential main grooves formed in a tread rubber at an inner region sandwiched by both shoulder regions and one or more circumferential ribs defined by two adjoining circumferential main grooves, and at least two circumferential fine grooves are formed in the circumferential rib.

Abstract: Sipes extending from one end of a block to the central area of the block and sipes extending from the other end of the block to the central area of the block (sipes 24, 28, 32 and 36) are inclined in directions opposite to each other. The sipes extending from one end of the block and the sipes extending from the other end of the block intersect a common line extending along the circumferential direction of the tire. Due to this structure, the number of portions of the sipes, which portions are located in the central area of the block, is made greater than that in the peripheral area of the block. The density of sipes is thus increased in the central area of a block where water tends to form when driving on ice, for improving braking and traction properties on ice.

Abstract: A lamella for use in a vehicle tire vulcanization mold has projections and depression, wherein the height of the projections and the depth of the depressions extend substantially parallel to a peripheral surface of the tire tread of the vehicle tire to be molded in the vulcanization mold. Each one of the projections has a highest point-shaped location or top. Each one of the depressions has a lowest point-shaped location or crater. The projections and depressions are distributed according to a substantially uniform areal division. The areal division is defined by dividing lines extending in a dividing plane preferably centrally positioned between a first plane defined by the tops and a second plane defined by the craters. The dividing lines are comprised of three sets wherein the dividing lines within each one of the sets extend parallel to one another and wherein the dividing lines of different ones of the sets intercept one another at an angle of substantially 60° so that a grid of triangles is formed.

Abstract: Disclosed is a pneumatic tire effectively controlling uneven wear occurring in the vicinity of a main groove even if a groove width of the main groove is narrowed due to change in tread radius during inflation. In the pneumatic tire, with regard to a zigzag-shaped main groove having the groove width narrowed during inflation among a plurality of main grooves provided on the tread surface, an inclination angle of a groove wall near the shoulder with respect to the tread surface is made relatively large in a bent portion near the shoulder, an inclination angle of a groove wall near the center with respect to the tread surface is made relatively large in a bent portion near the center, and regions where the inclination angles of the opposed groove walls are different from each other are uncontinuously arranged in the tire circumferential direction.

Abstract: A pneumatic tire which comprises a pair of right and left bead portions, a carcass layer disposed extending between the bead portions, a tread portion arranged at an outside of the carcass layer in a radial direction of the tire, a pair of side wall portions arranged at right and left sides of the tread portion and at least one pair of rubber members selected from a pair of rubber members constituted with a rigid rubber and arranged in the bead portions and a pair of rubber members disposed in the side wall portions, wherein at least one pair of rubber members selected from a pair of rubber members arranged in the bead portions and a pair of rubber members disposed in the side wall portions are constituted with rubber composition having a minimum value of a dynamic storage modulus within a temperature range of 200 to 250° C. which is 75% of a dynamic storage modulus at 50° C. or more.

Abstract: A tread pattern for a tire, the tread pattern being formed by elements in relief defined by grooves, some of these elements in relief being provided with at least one blind incision, that is to say, one which does not open into the grooves. These elements in relief include at least one cutout which opens into at least one groove defining these elements, and such that, on the running surface, each blind incision crosses at least one open-ended cutout of the same element, whatever the level of wear of the tire. Each of these open-ended incisions has a depth substantially equal to the depth of the blind incisions which it crosses and is filled with a filler material, the filler material having the characteristic of being gradually eliminated under the action of frictional contact with the ground during travel to form a channel of low depth which enables the air trapped in the blind incisions to escape.

Abstract: The present invention provides a pneumatic tire having a tread portion comprising a plurality of axially spaced apart essentially longitudinal grooves separating essentially longitudinal ribs. On at least one of said ribs, transverse grooves or cuts repeat in the circumferential direction to form first and second land portions wherein the first land portions comprise blocks having a circumferential length greater than that of the second land portions. Said second land portion acts as a sacrificial bridge which provides traction improvement and minimizes undesirable surface anomalies during the service life of the tire.

Abstract: A pneumatic tire comprising a tread which comprises block-shaped land portions and a plurality of specific sipes formed on the block-shaped land portions is disclosed. At least in one portion in the direction of the depth of the sipe, the sipe has an amplitude in the direction of the width of the sipe and extends in the transverse direction of the tire, and at least one portion of each sipe in the direction of the depth of the sipe is disposed at an offset position relative to an other portion of the sipe in a circumferential direction of the tire. The amplitude of the sipe in the present invention may change in the direction of the depth and the change may alternate from an increase to a decrease or from a decrease to an increase at one or a plurality of node positions disposed in the sipe in the direction of the depth of the sipe.

Abstract: A tread for a tire includes at circumferentially extending grooves having side walls contoured with upper and lower waveforms that are relatively staggered, or out of phase. The side walls provide alternating protrusions and recesses relative to a perpendicular reference plane passing through upper edges of the groove. A cavity is provided beneath upper groove edges for the entire circumference of the tread, which imparts flexibility and helps avoid the initiation of rail wear.

Abstract: A lamella for use in a vehicle tire vulcanization mold has projections and depression, wherein the height of the projections and the depth of the depressions extend substantially parallel to a peripheral surface of the tire tread of the vehicle tire to be molded in the vulcanization mold. Each one of the projections has a highest point-shaped location or top. Each one of the depressions has a lowest point-shaped location or crater. The projections and depressions are distributed according to a substantially uniform areal division. The areal division is defined by dividing lines extending in a dividing plane preferably centrally positioned between a first plane defined by the tops and a second plane defined by the craters. The dividing lines are comprised of three sets wherein the dividing lines within each one of the sets extend parallel to one another and wherein the dividing lines of different ones of the sets intercept one another at an angle of substantially 60° so that a grid of triangles is formed.

Abstract: A tire for vehicle wheels, provided with a tread band, includes a plurality of raised blocks confined between at least two longitudinal grooves, at least two transverse grooves meeting the longitudinal grooves, and a first and second series of sipes formed in the blocks to divide each block into a plurality of flexible portions. The flexible portions have a grip edge in the form of an acute angle on the outer rolling surface of the tread band. Each of the transverse grooves is confined between a first side, substantially normal to the outer rolling surface of the tread band, and a second side, diverging from the first side toward the outer rolling surface of the tread band. The second side of each of the transverse grooves has an orientation concordant with that of the sipes of a corresponding block, relative to the outer rolling surface of the tread band.

Abstract: A tread is provided with at least one rubber stud of orientation XX′ perpendicular or inclined with respect to the tread surface. The rubber stud has a side wall bounded by at least one incision and an outer end wall. The stud is joined to the tread at its base (the rubber stud part located farthest inward on the tread) and by at least one rubber connecting element joining the side wall of said stud to the rest of the tread. The projected length, on the tread surface in new condition and in the direction XX′, of the principal geometrical lines of the surfaces of intersection of all the connecting elements of each rubber stud, represents at least 80 percent of the contour perimeter, measured on the same surface, of each rubber stud. Preferably, the principal geometrical lines bounding the surfaces of intersection of the connecting elements are in the form of helixes around XX′, and the projected length of said lines is equal or close to 100 percent of the perimeter.

Abstract: A pneumatic tire comprises a tread with a plurality of sipes, in which one of opposed wall faces of the sipe is a concave face arc-shapedly curved over a whole of the sipe in a depth direction thereof and the other wall face thereof is a convex face just fitted to the above concave face, and a curvature of each of the concave and convex faces is substantially constant over a full length in a longitudinal direction of the sipe.

Abstract: A tire tread band for medium/heavy duty motor-vehicles having circumferential grooves confining three pairs of respectively center, intermediate and shoulder ribs. Respective tread blocks are defined along the center and intermediate ribs and they are confined by transverse cuts. The center cuts impart a cusp-shaped end conformation and a hollow-shaped end conformation to the respective blocks, and the shapes of said end portions mutually match. The intermediate cuts run in the linear extension of the center cuts to give the respective blocks a rhomboidal configuration. The tire can be alternately associated with a driving axle or a driven axle, by merely reversing its direction of rotation, so that the following results are selectively achieved: an increase in the traction capability by the intermediate blocks or an increase in the directional capability as a result of the mutual wedging between the center blocks at the ground-contacting area.

Abstract: The present invention provides a truck tire with a siping geometry to protect the main ribs of the tire's tread by delaying the onset of irregular wear and the growth thereof. The improved tire tread comprises a plurality of main ribs formed by grooves extending generally circumferentially around an outer surface of the tire forming a tread width for contacting the supporting surface. A plurality of sipes, positioned on both lateral edges of each one of the main ribs, provide protection for the main ribs to delay the onset of irregular wear. A pitch length and a sipe length are both selected to be within a certain range of values, as well as a ratio of the sipe length to the pitch length is selected. The sipes are preferably narrow in width having a maximum width dimension of about 0.40 millimeter.